los angeles ca 1/16/07 Why have we gained 24 minutes of sunlight in the PM and no gain of sunlight in the AM?

Answer 1

The cause of these is a phenomenon called the Equation of time.

The earth revolves around the sun at changing speeds, caused by the fact that it has an elliptical orbit. Kepler described exactly how in his Second Law of planetary motion. This motion is fastest in December and January, when the earth is closest to the sun.

The speed of rotation (the 24-hour day) cannot change but since, in its course around the sun, the earth moves further than average in December and January, this has the effect of making sunrise and sunset both happen about 1/3 of a minute later each day, cumulatively. Since the earth has moved farther than usual, it takes the sunrise and sunset about 1/3 of a minute more than normal to "catch up" with the extra distance we've traveled.

By early December, the north-south movement of the sun, caused by the seasons, is gradually starting to bottom out in a pattern known in trigonometry as a "sine curve." In November, this motion is still making the sunset happen earlier and earlier each day. By early December, however, it flattens out to the point where the seasonal change in the day's length becomes less than one-third of a minute per day.

Meanwhile, the Equation of time is still making everything happen later and later each day. In early December, the point is reached where that 1/3 of a minute per day starts to exceed the fading seasonal change and the sunset seems to start happening later each day.

The reverse happens in the morning. In the first half of December, both the seasonal change and the Equation of time are pulling in the same direction, making the sun rise later each morning. The seasonal movement fades completely by the solstice and even starts to reverse, but the 1/3 of a minute later each day continues to make its presence felt until about January 5th here in New York, when the northward movement of the sun finally wins out and the sunrise starts getting earlier.

AZ, by the way, singled out the Northern Hemisphere, but the same thing happens in the Southern too, and for the same reason. At their winter solstice (June in the Southern) the earliest sunset happens several days before the shortest day of the year and the latest sunrise several days later. The Southern summer solstice (last month) saw the earliest sunrise in early December and their latest sunset not until the first week of January.

Answer 2

Because the times of latest sunrise and earliest sunset are offset from the date of the equinox. In the northern hemisphere, the earliest sunsets occur about two weeks before the equinox, whereas the latest sunrises occur about two weeks after. The equinox is still the day with shortest total amount of sunshine.

Ergo, one easily notices in early January that sunsets are already getting later while sunrises seem to not be getting earlier (because they're not yet).

Answer 3

it became ben franklin's idea and he knew no longer some thing about california even as he dreamed it up. he had a tremendous type of "awesome" concepts, get it? is it organic or supernatural is what i ask your self about. ignore it!!

Answer 4

Can you repost the question. I didn't see it the first time.

Answer 5

Idiot